Seeing Double! What Is Fourth Nerve Palsy?

Our eyes are one of the most sensitive tools that our body plays host to. And for most people, sight is an asset not easily given up or compromised. With so many different conditions and injury related ailments, it can be hard to understand exactly what to avoid. As eye conditions tend to be quite complicated, this post will cover one; Fourth Nerve Palsy.

Fourth Nerve Palsy is a condition that affects the fourth cranial nerve. The fourth cranial nerve sends impulses to the superior oblique muscle; one of six muscles controlling the downward position of the eye.

Try crossing your eyes. When you do this, you’ll notice that it is impossible to keep your pupils in the center of your eye; they will always look slightly downwards. This is caused by the superior oblique muscle, and in turn by the fourth cranial nerve. This should give you some idea of how reliant our eye’s movement is on these muscles.

When the fourth cranial nerve fails, and the superior oblique muscle is unable to function. The result is an eye that constantly appears to look upwards. This can cause the afflicted to suffer from double vision, eye strain, headaches, dizziness, nausea and difficulty reading. Imagine trying to read a book, but through one eye, you can see something else entirely. As you can understand, this creates difficulty in all aspects of life. Even simple things that are taken for granted, such as driving, become impossible.

The fourth cranial nerve takes a very long route through the brain, and as such, can be very vulnerable to head trauma. This doesn’t mean that a little bump on the head will trigger fourth nerve palsy, but severe head injuries can.

Fourth Nerve Palsy can also be caused by several other things; brain tumors, aneurysms, meningitis, multiple sclerosis, strokes and more.

You can be suffering from fourth nerve palsy for several years before any symptoms appear. This is because our ability to bind and synchronize our eye’s movement diminishes with age; allowing the eye to roam free.

Solutions for Fourth Nerve Palsy range based on the severity of the case. For patients with minor correction needed, simply tilting your head can help. This helps to level out your eyes, which can eliminate double vision. You do this by tilting your head in the opposite direction to the faulty eye; so for palsy in the left eye you tilt right, and for the right eye you tilt left.

Sometimes this isn’t an effective treatment, though. For more serious cases, prisms are used! Prisms are small flat sided 3D shapes that fit onto the lenses of glasses. They change the image that the eye sees by changing the way that light is refracted into the eye. Essentially, to allow the user to see the same image through both eyes, we force the eye to see what we want. This eliminates the need for surgery in most cases and can resolve the problem completely. Though if the condition reaches a certain severity, and other measures fail, surgery is an option.

So, hopefully, you’ve learned a little bit about Fourth Nerve Palsy. If you have any symptoms of the condition, it is best to seek a medical professional as soon as possible.